IEC_60364-4-481-1993_scan.pdf

10NORMECEIINTERNATIONALEIECINTERNATIONAL364-4-481STANDARDPremiere editionFirst edition1993-07Installations electriques des batimentsPartie 4:Protection pour assurer la securiteChapitre 48:Choix des mesures de protectionen fonction des influences externesSection 481-Choix des mesures de protectioncontre les chocs electriques en fonction desinfluences externesElectrical installations of buildingsPart4:Protection for safetyChapter 48:Choice of protective measuresas a function of external influencesSection 481-Selection of measures forprotection against electric shock in relationto external influencesCEl 1993 Droits de reproduction rservs-Copyright-all rights reservedAucune partie de cette publication ne peut tre reproduite ni No part of this publication may be reproduced or utilized inutilise sous quelque forme que ce soit et par aucun pro-any form or by any means,electronic or mechanical,cd，lectronique ou mcanique,y compris la photocopie et including photocopying and microfilm,without permissionles microfilms,sans laccord ecrit de lediteur.in writing from the publisher.Bureau Central de la Commission Electrotechnique Intemationale 3,rue de Varemb Geneve,SuisseCommission Electrotechnique Internationale CODE PRIXInternational Electrotechnical CommissionPRICE CODEKIECMeAyHapoAHaR 3neKTpoTexHHecKaR HOMHCCHRPour prix,voir catalogue en vigueurFor price,see current catalogueIECVOL 12.364-4-4811EC:1993-72ELECTRICAL INSTALLATIONS OF BUILDINGSPart 4:Protection for safetyChapter 48:Choice of protective measures as afunction of external influencesSection 481-Selection of measures for protectionagainst electric shock in relation to external influences481.1 General481.1.1 The requirements of clause 481.2 indicate the measures for protection againstelectric shock defined in IEC 364-4-41 to be applied as a function of assessed conditionsof external influences.NOTES1 In practice,only the following conditions of external influences are relevant to the selection ofmeasures for protection against electric shock:BA-Qualification of persons;BB-Electrical resistance of the human body;BC-Contact of persons with earth potential.2 Other conditions of external influences have practically no influence on the selection andimplementation of measures for protection against electric shock,but should be taken into consideration forthe selection of equipment(see IEC 364-5-51,table 51A).481.1.2 Where,for a given combination of external influences,several protectivemeasures are permitted,the selection of the appropriate measure depends on localconditions and the nature of the equipment concerned.NOTE-For special installations or special locations,see IEC 364-7.481.1.3 Normative referencesThe following normative documents contain provisions which,through reference in thistext,constitute provisions of this section of IEC 364-4.At the time of publication,theeditions indicated were valid.All normative documents are subject to revision,and partiesto agreements based on this section of IEC 364-4 are encouraged to investigate thepossibility of applying the most recent editions of the normative documents indicatedbelow.Members of IEC and ISO maintain registers of currently valid InternationalStandards.IEC 364-4-41:1992,Electrical installations of buildings-Part 4:Protection for safetyChapter 41:Protection against electric shockIEC 364-5-51:1979,Electrical installations of buildings-Part 5:Selection and erection ofelectrical equipment-Chapter 51:Common rulesIEC 364-7-704:1989,Electrical installations of buildings-Part 7:Requirements for specialinstallations or locations-Section 704:Construction and demolition site installationsIEC 364-7-705:1984,Electrical installations of buildings Part 7:Requirements forspecial installations or locations-Section 705:Electrical installations of agricultural andhorticultural premises364-4-4811EC:1993-9-481.2 Measures of protection agalnst direct contact481.2.1 The measures of protection by insulation of live parts(see clause 412.1 ofIEC 364-4-41)and by barriers or enclosures(see clause 412.2 of IEC 364-4-41)areapplicable in all conditions of external influences.481.2.2 The measures for protection by means of obstacles according to clause 412.3of IEC 364-4-41 or by placing out of reach according to clause 412.4 of IEC 364-4-41 arepermitted in locations accessible only in accordance with the operating instructions toinstructed persons(BA 4)or skilled persons(BA 5)and if the following conditions arefulfilled:-the nominal voltage existing in such locations does not exceed the limit of voltageband Il;the rules stated in 481.2.4.1 and 481.2.4.3 are observed in the cases in question;the locations are clearly and visibly marked by appropriate signs.481.2.3 Protection against direct contact is not required in locations accessible only toinstructed persons(BA 4)or skilled persons(BA 5)duly instructed for the particularpurpose and if the following conditions are simultaneously fulfilled:-the locations are clearly and visibly marked by appropriate signs,and it is notpossible to gain access to them except by means of a special device;doors giving entrance to closed electrical operating areas shall allow easy escapeto the outside,and even if locked from the outside with a key,it is possible to openthem from the inside without the use of a key;for gangways,the minimum distances according to 481.2.4.2 and 481.2.4.3 areobserved.481.2.4 Minimum distances to be observed in operating and maintenance gangwaysNOTE-The figures indicated below are absolute minima;other considerations such as suitable workingpositions,escape facilities,etc.may make it necessary to adopt higher values.481.2.4.1 The following distances shall be observed where protection in accordance withclause 412.3 of IEC 364-4-41 is ensured(see figure 48A):a)Gangway width between obstacles or switch handles or betweenobstadles or switch handles and wall:700 mm minimumb)Headroom below panelling:2 000 mm minimumNOTE-The above dimensions apply after all parts of the panelling have been mounted and closed.